Method of making a sewn closure square bottom bag

ABSTRACT

A sewn closure square bottom gusseted bag, and process for making same, wherein the bottom construction thereof is such that one side of the bag is integral with a bottom panel, which panel is sealingly attached by sewing along one edge to the edge of the inner face of the other side of the bag. A flap may be attached to said other side which is either folded over the bottom panel or tucked between the bottom panel and said other side of the bag.

tilted Stats Patent [72] Inventors Stephen L. Coverstone;

Raymond K. Hughes, both of Richmond, Va. [21] Appl. No. 816,283 [22] Filed 1 Apr. 15, 1969 [23] Division of Ser. No. 702,065, Jan. 31 1968,

Pat. No. 3,473,724. [45] Patented Aug. 17, 1971 [73] Assignee lllloerner Waldorf Corporation Ramsey, Minn.

[54] METHOD OF MAKING A SIEWN CLOSURE SQUARE BOTTOM BAG 15 Claims, 14 Drawing lFigs.

[52] 11.5. C1 93/35 SB, 93/8 WA, 93/84 TW [51] lnt.Cl 1831b 1/26, B3 lb 1/90, B31b 45/00 [50] Field of Search 93/8 WA, 35 SB, 84 TW [56] References Cited UNITED STATES PATENTS 352,921 11/1886 Honiss 93/35 SB r 8 I a I "w l 1 11 3 1,734,287 11/1929 Cornell 2,445,757 7/1948 Belcher 2,749,966 6/1956 Roetger 3,319,540 5/1967 Stengle... 1. 3,336,845 8/1967 Lepisto .1 3,366,018 1/1968 Ciuitello v. 3,390,829 7/1968 Malby 3,408,904 11/1968 Thieken 3,437,016 4/1969 Malby 3,473,446 10/1969 Berghgracht.. 3,477,348 11/1969 Watters Primary ExaminerWayne A. Mors Jr. Attorney-Robert M. Dunning ABSTRACT: A sewn closure square bottom gusseted bag, and process for making same, wherein the bottom construction thereof is such that one side of the bag is integral with a bottom panel, which panel is sealingly attached by sewing along one edge to the edge of the inner face of the other side of the bag. A flap may be attached to said other side which is either folded over the bottom panel or tucked between the bottom panel and said other side of the bagv PATENTED AUG] 7 :sn I

SHEEI 3 [IF 4 METHOD OF MAKING A SEWN CLOSURE SQUARE BOTTOM BAG This application is a division of application Ser. No. 702,065, filed Jan. 31, 1968, now U.S. Pat. No. 3,473,724, issued Oct. 21, 1969.

BACKGROUND OF THE INVENTION Both square bottom bags and sewn closure bags are well known in the art and individually have distinctive advantages. The present invention, by combining both types of bags into one, also combines the advantages of both types of bags.

Square bottom bags have been utilized to advantage because of easy stacking and the availability of butt printing. These are advantages not possessed by pinch bottom bags having pillow corners".

Sewn closure bags provide advantages not possessed by the prior art square bottom bags. The sewn closure is easy to open by simply pulling out the thread. By comparison, prior art square bottom bags, generally having pasted closures, must be torn to open. Tearing may also lead to contamination of the bags contents with paper fibers-a disadvantage not occur ring with sewn closures. Silicone-coated paper bags must be scraped clean of silicone in the area of paste sealing, this step being unnecessary for the sewn closure. Further, where multiwall bags are provided with an inner plastic ply, heat-sealing the inner ply leads to difficulties when employing a pasted closure. By comparison, an inner plastic ply is still easily heatsealed after providing a sewn closure.

Bags of the present invention possess not only all of the above advantages but are also easily manufactured by simple folding and one step sealing, which may be utilized not only to manufacture paper bags but also plastic, multiwall, and laminated bags, the latter two being any combination of paper, plastic and/or other known materials.

SUMMARY OF THE INVENTION The present invention provides a square bottom container which is foldable into a flat condition when empty and has a parallelepipedal shape when filled, the container comprising,

when empty, a flattened tube having a front wall and a backwall connected by intermediate longitudinal sidewalls, a bottom panel integral with said backwall and closely adjacent at least part of the inner side of said front wall; and a seal connecting an edge of said bottom panel to an edge of said front wall.

Additionally, the present invention provides a method for producing a blank for square bottom containers comprising forming a flexible sheet material into a flat tube having a front wall and a substantially parallel backwall connected by intermediate longitudinal sidewalls; insetting one end of said front wall a short distance in the longitudinal direction of the tube between the sidewalls; and providing fold lines in said tube which are located transverse said front wall and substantially parallel to and spaced a short distance from the inset end of said front wall, transverse each sidewall and substantially perpendicular to said front wall and the fold line is said front wall, in each sidewallin the shape ofa triangle having its apex inter secting an intermediate point of the transverse fold line in each sidewall and having its base substantially parallel to said transverse fold lines and intersecting the corner formed by said inset end of said front wall and each sidewall, transverse said backwall and connecting respective ends of the bases of the triangles, and diagonal. each sidewall and connecting the endsof the fold line also transverse said back and a respective corner ofeach sidewall.

The present invention also includes forming said blank into a square bottom container by folding said. tube along the provided fold lines so that the apex of each triangle is substantially directed toward the apex of the other triangle, an outside portion of each sidewall on the opposite side of said diagonal fold line, an. inside portion of said: backwall betweenthe second transverse fold line and the end. of said backwall abuts an inside portion of said front wall between said inset edge and said transverse fold line in said front wall; and securing in a fixed relationship at least part of said front wall to said backwall.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a gusseted tube provided with a first embodiment of a cutting pattern shown in phantom.

FIG. 2 is a perspective view of an individual bag formed in accordance with the cutting pattern of FIG. I and provided with fold lines and a top flap shown in phantom.

FIG. 3 is a perspective view of the bag of FIG. 2 during initial folding of the bottom assembly.

FIG. 4 is a perspective view of the bag of FIG. 3 during further folding of the bottom assembly.

FIG. 5 is a perspective view of the bag of FIG. 4 during sealing of the bottom assembly.

FIG. 6 is a cutaway end view taken along lines 6-6 of FIG. 1 and FIG. 7 of a multiwall bag.

FIG. 7 is a perspective view of a gusseted tube provided with a second embodiment of a cutting pattern shown in phantom,

FIG. 8 is a perspective view of the second embodiment of an individual bag formed in accordance with the cutting pattern of FIG. 7 and provided with fold lines and a top flap shown in phantom.

FIG. 9 is a perspective view of the second embodiment of the bag of FIG. 8 during initial folding of the bottom assembly.

FIG. 10 is a perspective view of the second embodiment of the bag of FIG. 9 during further folding of the bottom as sembly.

FIG. 11 is a perspective view of a first alternative to the second embodiment of the bag of FIG. 10 during completion of the folding of the bottom assembly.

FIG. 12 is a perspective view of the sealing of the bottom assembly of the first alternative of FIG. 11 to the second embodiment of the bag. r

FIG. 13 is a perspective view of a second alternative to the second embodiment of the bag of FIG. 10 during completion of the folding of the bottom assembly.

FIG. 14 is a perspective view of the sealing of the bottom assembly of the second alternative of FIG. 13 to the second embodiment of the bag.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, prior to cutting individual bags from a part of a continuous tube, which may be either paper, foil, or plastic or multilayered combinations thereof including laminations, the tube is preferably provided with gussets. A cutting pattern is shown on the tube in phantom outline. In accordance with this pattern tube 1 may be divided along lines 2 into individual bags 3 of any desired length. Each bag has a front wall or face 4, sidewalls 5 and a backwall 6. Each sidewall Sis given the shape of bellows or gussets by means of fold line 7. In the cutting of bags 3 from tube 1, both or either top flap Sand/or bottom flap 10 may be provided as desired as shown in phantom with dotted lines 9. Omission of bottom flap 10 results in the first embodiment of bag 3 as shown in FIGS. 2 to 5.

In FIG. 2 there is shown an individual bag 3 separated from tube 1. Optional top flap 8 is shown in phantom. This bag is provided with a number of fold lines in the end assembly 11. Among the fold lines is line 112 which is transverse front wall 4 and parallel to inset edge 13. Connecting with the ends of and perpendicular to transverse fold line 12 are fold lines 114, which are transverse each sidewall 5. intersecting about the mid point of each fold line 14 are fold lines forming the apex ofisoscel'es triangle 15 having substantially equal sides 16 and a fold line base 17 substantially parallel to fold line 14. Baselines ll7 also intersect the ends of inset edge 13. Diagonal each sidewall. 5 and connecting the end of base 17 which does not intersect inset edge 13 with an opposite corner of sidewall 5 is fold line 18. Connecting the ends of fold lines 14 is fold line 19 which is substantially parallel to and aligned with fold line 12; connecting the ends of the baselines 17 is fold line 20 which is substantially parallel to and aligned with inset edge 13.

FIG. 3 shows the initial folding operation and forming of the bottom assembly 11 of the bag. In this folding operation, the gussets of sidewalls 5 are folded to lay in abutting relationship, and triangles are arranged to have apexes substantially pointed at each other. The portions of the sidewall around fold line 18 and base 17 are folded to provide gussets between backwall 6 and front wall 4.

As disclosed in FIG. 4, bottom assembly 11 is substantially completely folded by bringing bottom wall 6 into abutting relationship with at least a portion of top wall 4, thus exposing raw edges 21 which will eventually be sealed. The arrows in FIG. 4 indicate the direction of the final fold of the bottom assembly in order to facilitate sealing of raw edges 21.

The sealing of the bag with tape and stitching is shown in FIG. 5. This type of sealing is preferably used for paper bags, but where plastic bags are being made, heat sealing is more desirable. In the manufacture of multiwall or laminated bags having inner plastic plys, both a heat seal and sewn closure may be utilized.

FIG. 6 discloses a cutaway view of a representative multiwall bag having three outer plys of paper and one inner ply of plastic. In this type of multiwall bag, the plastic plys are heatsealed while the paper is sealed with stitching, alone, or including tape as shown in FIG. 5. Of course, the layers of paper and plastic may be staggered in the bottom assembly so as to avoid bulk in the folds.

A second embodiment of the present invention is shown in FIGS. 7-14. The main difference between this embodiment and the first embodiment is the provision of bottom flap 22 which necessitates some changes in the cutting of bag 3 from tube 1. A cutting pattern is shown in phantom in FIG. 7 with dotted lines 23. Inset edge 13 of FIG. 2 becomes a fold line in the second embodiment ofthe bag.

A phantom top flap 8 in addition to bottom flap 22 is shown in FIG. 8. When a bag is made with both flaps, it is desirable to make an adjacent bag from tube 1 which possesses neither a top flap nor bottom flap. Otherwise, the provision of fold lines in the bottom assembly is substantially the same for the second embodiment as it is for the first embodiment except for fold line 24 hingedly connecting bottom flap 22 to front wall 4.

Initial folding of end assembly 11 of the bag of the second embodiment as shown in FIG. 9 is substantially the same as initial folding of the end assembly of the bag of the first embodiment as shown in FIG. 3, except for the presence of bottom flap 22.

FIG. 10 discloses further folding of the bottom assembly of the bag of the second embodiment. The principal distinguishment of the second embodiment over the first embodiment is here more apparent as being the provision of bottom flap 22 which is subsequently disposed in alternative ways as shown in FIGS. 11 and 13. Thus, as shown in FIG. 11, flap 22 is simply folded over an integral portion of backwall 6 which now forms a bottom panel of the sack and is sealed with tape and stitching as shown in FIG. 12 or, where plastic is utilized solely as the material for the bag or as an inner ply, is preferably heat-sealed, either solely or in addition to the sewn closure. It is evident that sealing is effected on an opposite side of the bottom bag as compared with the first embodiment as shown in FIG. 5.

Fig. 13 discloses a second alternative of the second embodiment wherein top flap 22 is tucked between front wall 3 and the portion of b-ackwall 6 forming a bottom panel of the sack. As shown in FIG. 14, sealing may be effected by stitching, alone, or including tape, and/or by heat scaling in the case of plastic bags or plastic inner plys. Sealing is effected on the same side of the bottom of the sack as in the first embodiment of the bag shown in FIG. 5.

We claim:

1. A method for producing a blank for square bottom containers comprising:

a. forming a flexible sheet material into a flat tube having a front wall and a substantially parallel backwall connected by intermediate longitudinal sidewalls;

b. insetting one end of said. front wall a short distance in the longitudinal direction of the tube between the sidewalls; and

c. providing fold lines in said tube which are located I. transverse said front wall and substantially parallel to and wall and a short distance from the inset end of said front walls,

2. transverse each sidewall and substantially perpendicular to said front wall and the fold line in said front wall,

3. in each sidewall in the shape of a triangle having its apex intersecting the transverse fold line in each sidewall and having its base substantially parallel to said transverse fold line and intersecting the corner formed by said inset end of said front wall each sidewall,

4. transverse said backwall and extending between the respective ends of the transverse fold lines in the sidewalls,

5. also transverse said backwall and extending between the respective ends of the bases of the triangles, and

6. in each sidewall and extending diagonally from the ends of the fold line also transverse said backwall to a respective corner of each sidewall.

2. The method of claim 1 including forming said blank into a square bottom container by:

a. folding said tube along the provided fold lines so that 1. the apex of each triangle is substantially directed toward the apex of the other triangle 2. an outside portion of each sidewall between a diagonal fold line and a respective triangle base abuts an outside portion of each sidewall on the opposite sides of said diagonal fold lines, and

. an inside portion of said backwall between the transverse fold line extending between the triangle bases and the end of said backwall lies adjacent an inside portion of said front wall between said inset edge and said transverse fold line in said front wall; and

b. securing in a fixed relationship at least part of said inside portions of said front wall to said inside portion of said backwall.

3. The method of claim 1 wherein each sidewall is provided with gussets.

4. The method of claim 1 wherein said securing is accomplished by stitching a tape over the inset end of said front wall and the corresponding end of said backwall.

5. The method of claim 1 wherein the containers are at least partly plastic and said securing is at least partly accomplished by heat-sealing the inset end of said front wall and the corresponding end of said backwall.

6. The method of claim 1 wherein the containers comprise multiple layers selected from the group consisting of paper, plastic, metal foil, and textile fiber.

7. The method of claim 1 wherein said triangle is an isosceles triangle and said intermediate pint is the midpoint.

8. The method of claim I wherein an end flap is hingedly connected to said inset end of said front wall.

9. The method of claim 8 wherein said end flap is folded over that part of the backwall between said second fold line and said end of said backwall.

10. The method of claim 9 wherein said securing is effected by the overlapping of said end flap and said end flap is further secured to said backwall.

11. The method of claim 10 wherein the further securing is accomplished by stitching a tape over the end edges of said end flap and the folded edge formed by said second fold line in said backwall.

12. The method of claim 11 wherein the containers are plastic and the further securing is effected by heat-sealing said end flap to said backwall.

13. The method of claim 9 wherein said end flap is tucked between said front wall and said backwall.

14. The method of claim 13 wherein said securing is accomplished by stitching a tape over the inset end of said front wall 

1. A method for producing a blank for square bottom containers comprising: a. forming a flexible sheet material into a flat tube having a front wall and a substantially parallel backwall connected by intermediate longitudinal sidewalls; b. insetting one end of said front wall a short distance in the longitudinal direction of the tube between the sidewalls; and c. providing fold lines in said tube which are located
 1. transverse said front wall and substantially parallel to and wall and a short distance from the inset end of said front walls,
 2. transverse each sidewall and substantially perpendicular to said front wall and the fold line in said front wall,
 3. in each sidewall in the shape of a triangle having its apex intersecting the transverse fold line in each sidewall and having its base substantially parallel to said transverse fold line and intersecting the corner formed by said inset end of said front wall each sidewall,
 4. transverse said backwall and extending between the respective ends of the transverse fold lines in the sidewalls,
 5. also transverse said backwall and extending between the respective ends of the bases of the triangles, and
 6. in each sidewall and extending diagonally from the ends of the fold line also transverse said backwall to a respective corner of each sidewall.
 2. The method of claim 1 including forming said blank into a square bottom container by: a. folding said tube along the provided fold lines so that
 2. transverse each sidewall and substantially perpendicular to said front wall and the fold line in said front wall,
 2. an outside portion of each sidewall between a diagonal fold line and a respective triangle base abuts an outside portion of each sidewall on the opposite sides of said diagonal fold lines, and
 3. The method of claim 1 wherein each sidewall is provided with gussets.
 3. in each sidewall in the shape of a triangle having its apex intersecting the transverse fold line in each sidewall and having its base substantially parallel to said transverse fold line and intersecting the corner formed by said inset end of said front wall each sidewall,
 3. an inside portion of said backwall between the transverse fold line extending between the triangle bases and the end of said backwall lies adjacent an inside portion of said front wall between said inset edge and said transverse fold line in said front wall; and b. securing in a fixed relationship at least part of said inside portions of said front wall to said inside portion of said backwall.
 4. transverse said backwall and extending between the respective ends of the transverse fold lines in the sidewalls,
 4. The method of claim 1 wherein said securing is accomplished by stitching a tape over the inset end of said front wall and the corresponding end of said backwall.
 5. The method of claim 1 wherein the containers are at least partly plastic and said securing is at least partly accomplished by heat-sealing the inset end of said front wall and the corresponding end of said backwall.
 5. also transverse said backwall and extending between the respective ends of the bases of the triangles, and
 6. in each sidewall and extending diagonally from the ends of the fold line also transverse said backwall to a respective corner of each sidewall.
 6. The method of claim 1 wherein the containers comprise multiple layers selected from the group consisting of paper, plastic, metal foil, and textile fiber.
 7. The method of claim 1 wherein said triangle is an isosceles triangle and said intermediate pint is the midpoint.
 8. The method of claim 1 wherein an end flap is hingedly connected to said inset end of said front wall.
 9. The method of claim 8 wherein said end flap is folded over that part of the backwall between said second fold line and said end of said backwall.
 10. The method of claim 9 wherein said securing is effected by the overlapping of said end flap and said end flap is further secured to said backwall.
 11. The method of claim 10 wherein the further securing is accomplished by stitching a tape over the end edges of said end flap and the folded edge formed by said second fold line in said backwall.
 12. The method of claim 11 wherein the containers are plastic and the further securing is effected by heat-sealing said end flap to said backwall.
 13. The method of claim 9 wherein said end flap is tucked between said front wall and said backwall.
 14. The method of claim 13 wherein said securing is accomplished by stitching a tape over the inset end of said front wall and the corresponding end of said backwall.
 15. The method of claim 13 wherein the containers are at least partly plastic and said securing is at least partly accomplished by heat sealing. 